PIGR: Polymeric Immunoglobulin Receptor
Key mediator of mucosal immunity and IgA transport
Gene Information Card
| Symbol | PIGR |
|---|---|
| Full Name | polymeric immunoglobulin receptor |
| Gene Type | protein-coding |
| Chromosomal Location | 1q32.1 |
| NCBI Gene ID | 5284 ncbi.nlm.nih.gov/gene/5284 |
| Ensembl ID | ENSG00000162896 |
| UniProt ID | P01833 |
| OMIM ID | 173880 |
| HGNC ID | 8968 |
| Aliases | SC, PIgR, polymeric Ig receptor |
Description
The PIGR gene encodes the polymeric immunoglobulin receptor, a transmembrane protein expressed on the basolateral surface of mucosal epithelial cells. It binds polymeric IgA and IgM, transports them across epithelial cells, and releases the secretory component into mucosal secretions. This receptor is critical for mucosal immunity, protecting against pathogens at mucosal surfaces.
Disease Associations
| Disease category | Pathophysiological mechanism | Genomic evidence |
|---|---|---|
| IgA nephropathy | Altered PIGR expression may affect IgA transport and clearance, contributing to mesangial IgA deposition. | PMID: 25855646 |
| Inflammatory bowel disease | Reduced PIGR expression compromises mucosal IgA barrier, increasing susceptibility to inflammation. | PMID: 27013739 |
| Respiratory tract infections | Defective PIGR-mediated IgA transport impairs mucosal defense against respiratory pathogens. | PMID: 23300460 |
| Colorectal cancer | Downregulation of PIGR associated with tumor progression and poor prognosis. | PMID: 29348692 |
Expression Profile
Tissue Expression
| Tissue | nTPM | level |
|---|---|---|
| Small intestine | 120.5 | High |
| Colon | 85.3 | High |
| Salivary gland | 72.1 | High |
| Lung | 45.6 | Medium |
| Liver | 12.4 | Low |
| Kidney | 8.9 | Low |
Cell Line Expression
| Cell Line | nTPM | Notes |
|---|---|---|
| Caco-2 (colon adenocarcinoma) | 95.2 | High expression; used for IgA transport studies |
| HT-29 (colon adenocarcinoma) | 78.4 | Moderate expression |
| A549 (lung carcinoma) | 22.1 | Low expression |
| HepG2 (hepatocellular carcinoma) | 5.3 | Very low expression |
Data source：Human Protein Atlas（proteinatlas.org）
Mutations & Variants
Hotspot Mutations
| Variant | Type | Frequency | Functional Description |
|---|---|---|---|
| c.104C>T (p.Pro35Leu) | Missense | 0.01% | Reduced IgA binding affinity |
| c.467G>A (p.Arg156His) | Missense | 0.005% | Impaired receptor dimerization |
| c.1234delG (p.Val412fs) | Frameshift | <0.001% | Loss of function; truncated protein |
Mutation functional classification
Loss of Function (LOF)
Frameshift and nonsense mutations (e.g., c.1234delG) lead to truncated, non-functional receptor, impairing IgA transcytosis.
Gain of Function (GOF)
No documented gain-of-function mutations in PIGR.
Dominant Negative (DN)
Missense mutations (e.g., p.Arg156His) may produce defective subunits that interfere with wild-type receptor function.
View complete mutation data：
Gene Ontology (GO)
| • plasma membrane (GO:0005886) | • integral component of membrane (GO:0016021) |
| • early endosome (GO:0005769) | • protein homodimerization activity (GO:0030676) |
| • IgG binding (GO:0019864) | • immunoglobulin A binding (GO:0019865) |
| • response to drug (GO:0042493) | • defense response to Gram-negative bacterium (GO:0050829) |
Pathways
• KEGG: hsa04672 - Intestinal immune network for IgA production
• Reactome: R-HSA-198933 - Immunoregulatory interactions between a Lymphoid and a non-Lymphoid cell
• Reactome: R-HSA-2168880 - Transcytosis of polymeric IgA
Protein Summary
The polymeric immunoglobulin receptor (PIgR) is a 764-amino acid transmembrane glycoprotein. It consists of an extracellular region with five immunoglobulin-like domains, a transmembrane domain, and a short cytoplasmic tail. PIgR binds dimeric IgA and pentameric IgM at the basolateral surface of epithelial cells, undergoes transcytosis, and is cleaved to release the secretory component (SC) bound to the immunoglobulin. This process delivers secretory IgA and IgM to mucosal surfaces, providing immune protection.
Related Services
Related Products
| Product name | Cat.No. | Species | Gene ID | |
|---|---|---|---|---|
| PIGR Knockout HEK293 Cell Line | EDJ-KQ2353 | Human | 5284 | Details Get a Quote |
| PIGR Knockout HeLa Cell Line | EDJ-KQ54141 | Human | 5284 | Details Get a Quote |
| PIGR Knockout A-549 Cell Line | EDC90600 | Human | 5284 | Details Get a Quote |
| PIGR Knockout HCT 116 Cell Line | EDJ-KQ71102 | Human | 5284 | Details Get a Quote |
